Steering indicator for aircraft



.Oct. 1, 1929. 5, WUNSCH 1,729,850

STEERING INDICATOR FOR AIRCRAFT F'led March 21. 1928 Patented Oct. 1, 1929 umrsn STA-TIES TPATIENT OFFICE- QUIDO WU'NSCH, OF 'STEGLITZ, NEAR BERIJN, GERMANY, ASSIGNOR TO ASKANIA- WERKE A.-G'. VORMALS CENTRALWERKSTATT DESSAU UND' CARL BAMBERG-FRIE- vIDIEITAU', OF IBEBLIN-FRIEDENAU, GERMANY, A CORPORATION OF GERMANY srnn'ame INDICATOR non AIRCRAFT Application filed March 21, 1928, Serial No. 263,518, and in Germany March 28, 1927.

It is already known in the case of aircraft with a crew of two or more persons, to detail the observation Work to an observer. In orderto facilitate communication with the pilot, it has been proposed to have the observer turn the casing of the compass watched by the pilot, in which case a direction indicator is automatically operated, which remains operative until the pilot, by a corresponding steering turns the aircraft in the direction desired by the observer. The .arrangement is preferably. done in such a manner that the observer sets a pointer adjustable in front of a compass card and positively connected to the compass casing, so that it turns the latter to the same amount in the opposite direction. The operation of the direction indicator is preferably done electrically, namely the magnetic needle, or an arm secured to it, is arranged between two casing contacts, so that when on deviating to one or the other direction, it closes one of two ciry cuits and in that way operates an electromagneti'c direction indicator.

' Thedrawback of this arrangement is that the closmg of the electric contacts is not a perfect one, as' the directional force of the d magnetic needle is too small, and owing to constant vibrations during the flying, a good contact of the needle or of the arm secured to it, with the contact-of the casing cannot be obtained. For that reason, it has been al ready proposed also to efiect the control or steerin by. means of selenium cells, but this kind 0 control presents difiiculties and is unreliable.

The present invention eliminates the drawback in question by using as the source of power a pressure medium) (for instance compressed air) acting on a servo-motor and throttled to a greater or less extent by the 1 movement of the compass casing relatively to the magnet system. A construction according to the invention is illustrated byway of example in the accompanying drawm in Whl Figure 1 is a verticalsection through the compass,

F1gure-2 is a of Figure 1 on'line 2 AM. a

when the aircraft has-taken e The casing of the compass T is marked H. i

It is mounted in a rotatable manner. The rotation can be eflected by means of a spindle W which is turned by the observer in the known manner, for instance by his setting a.

pointer on a compass card arranged in front of his seat. The spindle W carries a worm S which is in mesh with the worm rim or wheel S mounted on the compass casing.

The compass itself can be of any desired construction. In the construction shown in the drawing, the magnets are mounted on a point or'pin a. To the oscillating magnet system, or to the card, is secured a spindle b projecting upwards, and bearing an'eccentrically mounted disc 0. Above and below the disc 0 are respectively arranged pairs of nozzles or mouthpieces d, e, g, and g. The nozzles d and 6 lead into a upper part of the compass, to which a pressure medium, preferably compressed air, is supplied through a pipe 71.. The compressed air passes through. the pipe'i and constantly escapes through the two nozzle shaped parts and e.

The energy of flow of thetwo escaping jets is determined by the nozzles f and g. A pressure difference gauge of the well known ollow space in the kind, connected to these nozzles,.will be in the zero position when the energy of flow is the same. In the path of the two jets is arrangedthe disc 0, controlled by the magnet system. In the nornial position that is to say rescribed direction, the action of the thrott ing pres:

sure of each of the two air yets on the nozzles f and is reduced. bthe dlsc d to about half the va ue it would ot erwise have (Figure 4). When the aircraft deviates from its course,

the disc 0 will tend to assume for instance the position shown in Figure 3. The thrpttling ressure on the nozzle 9 will be mor that on the nplgllgf decreased, in the position shown igure 3, the throttling pressure on thenozz'le 9 W111 indicate the full enezrzgy of flow of the jet escaping from the no e, while the action of the jet escaping from the nozzle (1, on the nozzle f become zero. The pressure diflerence gauge connected to the nozzles f and 9 will have reached its greatest possible deflection.

In the arrangement illustrated and de-' scribed, the reaction forces of the air jets will also cancel each other in the normal position of the aircraft, as the torques acting on the eccentric disc 0 will be of the same .value and of the opposite direction in the said position.

The nozzles f and g are connected by pipes m and'n to the two ends of a cylinder 0 in which travels a piston 7). When the compressed air can enter but one of the nozzles f or g an excess of pressure will be produced in the corres ending cylinder end, and the piston 39 will be moved accordingly inone or in the other direction. The movement of the piston can be utilized either for setting a direction indicator I which informs the pilot in which direction he has to steer, or for effecting the steerin automatically.

As soon as the piibt has turned in the direction desired by the observer the compass cas-' ing will again have turned back-relatively to the disc 0 to such an extent that both nozzles will be partially covered, whereupon the piston will be brought back again-to its central position by any desired means, for instance by two weak springs p of the-same power acting on the two faces of the piston, so that the direction indicator will cease to act. The piston could be used of course also directly for the steering of the aircraft, as with a suitable. dimensioning of the nozzles, of the air pressure etc. sufficientl lar e forces can be produced in order to bring a out by means of the piston itself the steeringmovements,.-for instance a twisting of the pressure surfaces, so that the driver himself need not do anything for turning the aircraft to the proper course.

It goes without saying that the construction shown in the drawing can be modified in many respects. Thus for instance the arran ement can be used in the same way for a flui compass. In place of the servomotor constituted by the piston and cylinder, a diaphragm can be used which is moved by the varying pressure to one or to the other side,

and the-eccentric disc used for the throttling of the pressure medium could be replaced by a cylinder segment, in which case the nozzles would have to bearranged radially of the axis of the magnet system, that is to say,

turned to 90 relatively to the position shown the overcoming of the relatively great tion will probably present great difficulties. s

in the drawing. The/.outlet openings (1 and e for the pressure medium can also be connected directly to the pi es m and n by inserting other throttling evices, for instance valves, cocks or the like, which are adjusted to suit the osition of the compass casing relcasing can be any desired. In place of mechanical ones could be used electric or hydraulic devices.

If required, separate means can be provided for intensifying the pressure produced by the device behind the piston, in order to obtain a sufiicient setting force, more particularly when the apparatus is to be used for automatic steering.

. Both actions can be of course combined, that is to say, a direction indicator which is visible to the pilot could be operated, and at the same time the steering automatically effect ed. a

Asa rule, two nozzles will be used and two compressed air pipes in order to produce a movement of the servomotor in two direc- 1. A steering indicator for aircraft comprising a rotatable compass casing, means "for rotating said casing according-to the direction to be followed, a nozzle in said casing, means for conducting a fluid under pressure to said nozzle, a second nozzle positioned opposite to and adapted ,to receive at least a part of the flow from said first nozzle, a compass needle in said casing, and means interposed between said nozzles and controlled by said needle adapted to vary the proportion of fluid exchanged between said nozzles.

2. A steering indicator for aircraft comprising a rotatable compass casing, means for rotatin said casing according to the direction to e followed, a pair of nozzles in said casing, means for conducting a fluid under pressure to said nozzles, a second pair of nozzles positioned opposite to and adapted to receive at least a part of the flow from said first pair ofnozzles, respectively, a compass needle, in said casing, and means interposed between said nozzles and controlled by said needle adapted. to vary the pro ortion of fluid exchanged between said nozz es.

3. A steering'indicator for aircraft comprising a rotatable compass casing, means for rotating said casing according to the direction to be followed, a nozzle in said casing, means for conducting a" fluid under pressure to said nozzle, a second nozzle positioned opposite to and adapted ,to receive at least a part of the flow from said first nozzle, a compass needle in said casing, means interposed between said nozzles and controlled by said needle adapted to vary the proportion of fluid exchanged between said nozzles and indicatatively tot emagnet needle, but in such casm ing means ada ted to be controlled by the fricfluid received b the second nozzle.

4. A steering indicator for aircraft com;

prisinga rotatable compass casing, means for rotating said casing according-to the direction 'to be followed, a pair of nozzles in said casing, means for conducting a fluid under pressure to said nozzles, a second pair of nozzles positioned opposite to and adapted to receive at least a part of the flow from said first pair of nozzles respectively, a compass needle in said casingflneans interposed between said nozzles and controlled by-said needle adapted to' vary the proportion of fluid exchanged between said nozzles and indicating means adapted to be controlled by the difference of fluid pressure in the second pair of nozzles.

5. A steering indicator for aircraft comprising a rotatable compass casing, means for rotating said casing according to the direction to be followed, a. nozzle in said casing, means for conducting a fluid under pressure to said nozzle, a second nozzle positioned opposite to and adapted to receive at least a part of the flow from said first nozzle, a compass needlerin said casing, and an eccentric disc rotating with the compass needle inter-.

posed between said nozzles and controlled by said needle adapted to vary the proportion of-fluid exchanged between said nozzles.

6. A steering indicator for aircraft comeo prising a rotatable compass casing, means for rotating said casing according to the direction to be followed, a pair of nozzles in said casing, means for conducting a fluid under pressure to said nozzles, a second pair of nozzles positioned opposite to and adapted to receive at least a part of the flow fromsaid first pair of nozzles respectively, a compass needle in said casing, and an eccentric disc rotating with the compass needle interposed 4 between said nozzles andcontrolled by said needle adapted to vary the proportion of fluid exchanged between said nozzles.

In testimony whereof I have aflixed my signature.

' GUIDOWI'TQNSCH. 

